A recent large European cohort study published in the journal BMCmedicine explored the impact of healthy lifestyle factors on colorectal cancer incidence and mortality. The specific experiments were as follows.
Lifestyle and colorectal cancer risk.
Lifestyle plays an important role in the risk of colorectal cancer (CRC). Many studies have explored the association between CRC and individual lifestyles, such as overweight, low physical activity, smoking, alcohol consumption, and diet; each of these factors is associated with the risk of developing CRC.
This study applied cohort data from the European Prospective Study on Cancer and Nutrition (EPIC) to investigate the joint effect of various healthy lifestyles on the risk of developing CRC. The researchers also estimated population-attributable risk measures. Population-attributed risk scores can be used to help determine the proportion of disease risk that can be prevented at a given time if a particular risk factor or combined risk factor is missing in a given population.
The EPIC subject population was recruited from 10 European countries between January 1992 and December 2000. A total of 347,237 adult men and women provided information on their diet and lifestyle habits at the start of the study.
To assess the correlation between CRC and lifestyle, the researchers proposed the concept of a Healthy Lifestyle Index (HLI). The presence of one of the following five healthy lifestyle influences assigned a score of 1 to individuals in their EPIC cohort
* Body mass index of 18 to 25 kg/m2 or waist circumference <2350 px for men and <2000 px for women.
※High or very high intensity physical activity: manual or heavy work occupations, men with metabolic equivalents >57 and women with metabolic equivalents >82.
※Non-smokers: never smokers or quitters.
※ controlled alcohol consumption (men who drink two or fewer standard glasses of alcohol per day and women who drink one or fewer standard glasses of alcohol per day)
*Healthy diet: consume more fruits, vegetables, dietary fiber, fish, nuts, garlic and yogurt, and consume less red or processed meats.
A score of zero represents the lowest healthy HLI and a score of five represents the healthiest HLI.
The median follow-up period was 12 years, and 3759 colorectal cancers were identified (2369 colon and 1390 rectal cancers). Those with a higher HLI were more likely to be female and tended to have a higher level of education.
For the individuals studied, the incidence of CRC was decreasing with higher HLI (number of healthy lifestyle influences) compared to HLI 0 or 1 (Table).
Table Effect of HLI on CRC risk
HLI
2
3
4
5
CRC reduction
13 %
21%
34%
37%
Note: CRC = colorectal cancer; HLI = Healthy Lifestyle Index; P < 0.001
Assessment of population-attributable risk showed CRC cancer location, with gender-specific risk gradients associated with CRC risk. 36% of rectal cancer cases in men and 20% of colon cancer cases in women were attributable to nonadherence to all five healthy lifestyles. When different combinations of lifestyle influences (two to four factors compared to zero or one factor) were analyzed, the risk was not lower for any two factor combinations, but the combination of healthy weight, not smoking, and healthy diet was associated with the lowest possible risk as was the combination of all five lifestyle factors.
Such lifestyle studies, although not randomized controlled studies, rely on their prospective design, long-term follow-up, and large sample sizes to provide some compelling evidence that lifestyle changes, particularly healthy weight, nonsmoking, and healthy diet, reduce CRC. lifestyle changes are essentially costless and have no risks or side effects. Doing so will not only reduce mortality from CRC, but also from many other chronic diseases and cancers.
Therefore, we should not simply go for colorectal cancer screening, but also pay attention to our lifestyle and change ourselves to have a healthy lifestyle so as to reduce the incidence and mortality rate of colorectal cancer. To prevent colorectal cancer, we should start from changing our lifestyles.